How to increase Outlook email size limit to… No Limit?

by | Mar 16, 2022 | How-to's

How to increase Outlook email size limit? Problem solved. There is no limit anymore!

How to increase Outlook email size limit?

This question haunts the web for too many years.
Asking Google returns millions of (bad) answers:

Searching "how to increase Outlook maximum email size limit" in Google.

Increasing Outlook email size limit, a good idea?

In fact, this question may not be the right question to ask.
Because would we configure Exchange or Exchange online to send very large Outlook emails, like 150 MB, 500 MB, 1 GB or more, (yes this can be done, see below), this would be of no use.

Default Message Size Restriction in Exchange Server admin

This is the MS Exchange Admin panel enabling to configure the maximum message size.

Why Increasing Outlook email size limit might not be of any use?

Simply because such large emails would never reach their recipients.
Almost no email server accepts emails over a 50 MB size these days.
Our over-sized emails would simply get rejected:

Your message wasn't delivered to anyone because it is too large! The limit is...

Why do I need to send such large emails?

This is the first question we should ask ourselves rather than wondering how to increase Outlook, Exchange or Office 365 limits in terms of maximum email size.

The answer is easy:

  • Because we need to send / share large attached files to / with others.
    We have never seen even a 1 MB email containing only text, right?
  • Because attaching files to an email (using Outlook or any other email client) is the easiest and fastest way to send files to others.
  • Because we have been attaching files to our emails for so long that we can’t imagine doing otherwise to share files with others distant (an even sometime local) users.

In fact, “How to increase Outlook email size limit” and “How to increase Outlook attachment size limit” may not be the right questions to ask.

Because what we are looking for is a solution that would allowing us to:

  • Attach large and even very large files to our Outlook emails (let’s say up to 250 GB unit size with no email size limit), as any other file.
  • Then send these emails as usual (clicking the Outlook Send button).
  • Have some kind of magic doing the following:
    • Uploading our Outlook attached files to cloud storage (what about OneDrive)
    • Sharing them with the email recipients
    • Replacing them by OneDrive shortcuts before our email is finally sent
    • All this, automatically. 

This is exactly what Attach2Cloud for Outlook and OneDrive does (plus other interesting things).

With Attach2Cloud, attach very large files (up to 250 GB unit size) to your Outlook emails as any other files (without any email size limit).

Let’s say we’d like to send these huge files below (18 GB of video files):

6 large video files (18 GB) to be attached to a Microsoft Outlook email.

Let’s create an Outlook email and drag & drop these big files to our email. 
No, we WON’T get the usual “The file you’re attaching is bigger than the server allows.” error dialog:

The file you're attaching is bigger than the server allows. Try putting the file in a shared location and sending a link instead.

Instead, our very large files get instantly (i.e. one second later) and automatically attached to our Outlook email:

6 large video files (18 Gigabytes in total), attached to an Outlook email in one second!

As you can see, Attach2Cloud has added The Attach to Cloud cloud tag for MS Outlook attachments exceeding the Outlook maximum allowed email size limit to the attached file names. So you know that these files will be uploaded to OneDrive when you send your email.
The size of the attached files is only 1 KB. In fact these files have not really been attached to the email. The attached files files you see are placeholders created by Attach2Cloud.

Let’s simply click on Send (as usual).
Our email is put in the Outlook Outbox (as any other email).
That’s it.
We can continue using Outlook to read, sort, create or send other emails.

See the large attached files being uploaded to OneDrive automatically by Attach2Cloud

If we look at our Outlook Outbox, we can see our email being processed.
Look at the email subject, Attach2Cloud is uploading the email attached files to OneDrive and displaying the progression of the upload: “Starting to upload 6 attachments to OneDrive…” then “Uploading attachment 1 of 6 to OneDrive” etc.

Now let’s have a look at our email in the Outlook Inbox of one of his recipients.
Its size is only 79 KB: 

The size of the received email (with the large video attached files replaced by OneDrive shortcuts by Attach2Cloud) is only 79 KB.

And our extra large attached files have been replaced by OneDrive shortcuts: 

The received MS Outlook email with attached OneDrive shortcuts created by Attach2Cloud in replacement of the large attached files

And it is of course the same for the copy of this email stored in our Outlook Sent Items folder:

In the MS Outlook Sent Items folder, the sent email with the OneDrive shortcuts created by Attach2Cloud in replacement of the large attached files

Thanks to Attach2Cloud, the sender and the recipients of this email are now able to collaborate using the same unique copy of these very large files stored in OneDrive.

Large Outlook email issues? Attached files too large to be sent using Outlook?
Problem Solved!

Thanks to Attach2Cloud, the size of the Outlook email is now virtually unlimited.
You can attach as many large files as you need to your Outlook emails (provided their unit size remains under 250 GB).
You are certain that the recipients of your Outlook emails containing large attached files (up to 250 GB unit size) will be able to get your emails and your files whatever their size is.

Try for Yourself!

Enjoy sending Multi-Gigabyte Outlook emails to your colleagues and friends, Download a free fully functional evaluation copy of Attach2Cloud for Outlook and OneDrive.
It takes less than one minute to install.

Then see for yourself how easy it is to send extra-large (or not) Outlook attached files, thanks to Attach2Cloud:
Once Attach2cloud is installed, start Outlook, create a new email, attach some files (large or not) to it and send it. That’s it. You have nothing special to do!

Attach2cloud works with any 32-bit or 64-bit version of Outlook 2013, Outlook 2016 and Outlook 2019 running on Windows 7, Windows 8.1 or Windows 10, and OneDrive for Business (the version of OneDrive available through Office 365 subscriptions).

In case you are using Outlook but, for any reason, not using OneDrive for Business, we have other solutions like Z-OptimiZr for Microsoft Outlook and ZipMail Real-Time for MS Exchange Server to help reducing the size of your Outlook emails.

Some questions about Attach2Cloud?

For a more complete description of Attach2cloud, please see the Attach2Cloud home page and the Attach2Cloud Usage Cases page.
Please also have a look at the the Attach2Cloud Q&A page and don’t hesitate to contact us, we’ll always be most pleased to answer any questions you may have about Attach2Cloud.

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Last updated: Jan 19, 2023